Process for the recovery of silver from zinc plant calcines and neutral or low acid leach residues with thiourea

摘要

A process for the recovery of silver from zinc calcines, or neutral or low acid leach residues, is disclosed. The process comprises the steps of leaching a silver containing zinc calcine or a neutral or low acidic sulphate solution containing from 0.1-20 g/l thiourea at 30-85°C and pH 1-5 to solubilize more than 85% of the silver, and recovering the solubilized silver by adsorption onto activated carbon, or an ion-exchange resin, or by cementation on iron or zinc dust.